XM3 made her first appearance in Chapter 10-2. She and her team were tasked to pick up AR M4A1M4A1 in a small outpost after M4A1 managed to enter the restriction zone with the help of Angelia. After confirming each other's identity with M4A1, they boarded the transport train.
They engaged in conversation on board, and exchanged information regarding the current situation. From XM3, M4A1 learned that their transport was heading to the frontline. Commander was in charge of operation vanguard, to hunt down the Sangvis' Mastermind together with the army. M4A1 also learned about the current situation of AR Team, in which SMG RO635RO635 has joined the team. From the conversation XM3 revealed that it's been just 2 years since she joined Griffin, and how she accepted that there was no real death for tactical dolls as they can be repaired and their memory logs can be redownloaded.
It's when M4A1 asked XM3 to patch her to the Commander, until their transport train was hit by an explosion. Turned out that Sangvis has set an ambush for them. XM3 contacted the Commander, but Griffin main force was too far from the site. It would need some time for them to get there. XM3 informed that Commander has turned over the command authority to M4A1, so she can lead the dolls to fight back.
Sangvis offensive was relentless, and breaking through it proven to be very difficult. M4A1 ordered the surviving dolls to pull back and regroup to launch another charge, but XM3 told her over the radio that there weren't so many doll left that can still move. XM3 hasn't finished her words when rain of shells hit the vicinity. M4A1 frantically called XM3 out but a clear voice inside her digimind told her that XM3's signal has vanished.